From patchwork Wed Oct 12 14:32:17 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [lucid] NLM: Don't hang forever on NLM unlock requests - CVE-2011-2491 Date: Wed, 12 Oct 2011 04:32:17 -0000 From: Paolo Pisati X-Patchwork-Id: 119219 Message-Id: <1318429938-16867-3-git-send-email-paolo.pisati@canonical.com> To: kernel-team@lists.ubuntu.com From: Trond Myklebust NLM: Don't hang forever on NLM unlock requests If the NLM daemon is killed on the NFS server, we can currently end up hanging forever on an 'unlock' request, instead of aborting. Basically, if the rpcbind request fails, or the server keeps returning garbage, we really want to quit instead of retrying. Tested-by: Vasily Averin Signed-off-by: Trond Myklebust Cc: stable@kernel.org CVE-2011-2491 BugLink: http://bugs.launchpad.net/bugs/869237 commit upstream 0b760113a3a155269a3fba93a409c640031dd68f Signed-off-by: Paolo Pisati --- fs/lockd/clntproc.c | 8 +++++++- include/linux/sunrpc/sched.h | 1 + net/sunrpc/clnt.c | 3 +++ net/sunrpc/sched.c | 1 + 4 files changed, 12 insertions(+), 1 deletions(-) diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c index c81249f..c325a83 100644 --- a/fs/lockd/clntproc.c +++ b/fs/lockd/clntproc.c @@ -709,7 +709,13 @@ static void nlmclnt_unlock_callback(struct rpc_task *task, void *data) if (task->tk_status < 0) { dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status); - goto retry_rebind; + switch (task->tk_status) { + case -EACCES: + case -EIO: + goto die; + default: + goto retry_rebind; + } } if (status == NLM_LCK_DENIED_GRACE_PERIOD) { rpc_delay(task, NLMCLNT_GRACE_WAIT); diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h index 4010977..46c6514 100644 --- a/include/linux/sunrpc/sched.h +++ b/include/linux/sunrpc/sched.h @@ -55,6 +55,7 @@ struct rpc_task { struct rpc_message tk_msg; /* RPC call info */ __u8 tk_garb_retry; __u8 tk_cred_retry; + __u8 tk_rebind_retry; /* * callback to be executed after waking up diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index d838bea..b0c5646 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -1052,6 +1052,9 @@ call_bind_status(struct rpc_task *task) status = -EOPNOTSUPP; break; } + if (task->tk_rebind_retry == 0) + break; + task->tk_rebind_retry--; rpc_delay(task, 3*HZ); goto retry_timeout; case -ETIMEDOUT: diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c index 570da30..ac94477 100644 --- a/net/sunrpc/sched.c +++ b/net/sunrpc/sched.c @@ -784,6 +784,7 @@ static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *ta /* Initialize retry counters */ task->tk_garb_retry = 2; task->tk_cred_retry = 2; + task->tk_rebind_retry = 2; task->tk_priority = task_setup_data->priority - RPC_PRIORITY_LOW; task->tk_owner = current->tgid;